BACKGROUND: Prolonged heart rate-corrected QT (QTc) interval is frequently observed in subarachnoid hemorrhage (SAH). This study was conducted to determine the relationship between QTc interval and neurological outcome during the acute posthemorrhagic period after aneurysmal SAH.METHODS: We studied 71 patients undergoing surgery who were admitted within 24 h after the onset of aneurysmal SAH. Standard 12-lead electrocardiography was performed on admission (T1) and at 1 and 7 days after operation (T2 and T3). QT intervals were corrected by heart rate according to the Fridericia formula. The Glasgow Coma Scale (GCS) score was calculated over the period T1-T3. Neurological outcome was assessed using the Glasgow Outcome Scale at hospital discharge.RESULTS: Among the 71 patients, 31 had an unfavorable neurological outcome. Although QTc interval prolongation improved in patients with a good outcome, QTc interval prolongation continued in patients with an unfavorable outcome. The areas under the receiver-operator characteristic curves showed that the QTc and GCS score at T3, and the Hunt and Hess grade were significant predictors of an unfavorable neurological outcome. The threshold value, sensitivity, and specificity for the QTc at T3 were 448 ms, 73% [95% confidence interval (CI), 68-78], and 93% (95% CI, 90-96), respectively.CONCLUSION: This study confirms that QTc interval prolongation continues in the SAH patients with an unfavorable outcome but that QTc interval prolongation improves in patients with a good outcome, suggesting that a QTc interval of more than 448 ms at 7 days after operation is a predictor of neurological outcome after SAH.